25mm Countersink UltimateCut 4-Flute HSS RUnaTEC Coating 90° Shaft With Three Flats - Ruko GmbH

Take advantage of the combination of high cutting performance, reduced feed force and a secure shank design for faster, cleaner chamfering operations; order the countersink directly via Metav Werkzeuge or consult our specialists for application advice.

UltimateCut 4S Countersink (25 mm, 90°) by Ruko — HSS, RUnaTEC-coated

UltimateCut 4S is a precision 90° countersink engineered for efficient chamfering in steel, combining four‑flute geometry with a robust HSS substrate for smooth results in both machine and manual operations

• HSS with RUnaTEC coating
• 90° angle for standard chamfers
• 4‑flute geometry for smooth cutting
• Shank with three flats for secure clamping

Faster production through optimised cutting geometry

The UltimateCut 4S delivers measurable productivity gains thanks to its 4‑flute design and HSS core. The additional cutting edges distribute the load more evenly, which lowers the required thrust during chamfering and enables up to 50% faster countersinking in many setups. For production environments that alternate between bench work and machine use, this equates to shorter cycle times and reduced operator fatigue without compromising finish quality.

Secure clamping and vibration‑free operation for consistent results

A shank with three flats provides reliable gripping in standard chucks and collets, preventing slippage even under higher feed forces. Combined with the RUNaTEC coating, the tool runs exceptionally quietly and produces an optimal countersink finish free from ratter marks. This stability reduces rework and supports reproducible results across batches, which is particularly valuable where component interchangeability is critical.

Explained cutting data and material suitability

Designed specifically for steel, the countersink performs best at feeds up to 0.24 mm/rev when the cutting force does not exceed 800 N. The RUNaTEC surface treatment enhances wear resistance and reduces built-up edge, extending tool life compared with uncoated HSS equivalents. In practical terms, the combination of coating and geometry means more holes can be countersunk per tool, with reports of up to 3× more countersinking achievable under comparable conditions.

Practical benefits for the workshop and quality control

This countersink supports both stationary and manual applications, making it suitable for small series, maintenance tasks and production runs. The 90° chamfer angle conforms to common assembly standards, simplifying inspection and ensuring reliable seating for fasteners. Fewer tool changes and more consistent finishes reduce interruption to workflow, while the improved material removal characteristics help maintain dimensional tolerances with less operator intervention.

For reliable performance in chamfering and to discuss the best variant for specific steel grades, contact Metav Werkzeuge for expert advice and prompt supply from Emmerich.

Technical data

• Article number: 4000605556NW
• Product: UltimateCut 4S countersink, 25 mm, 90°
• Packaging unit: 1

Core specifications

• Diameter: 25 mm
• Countersink angle: 90°
• Flutes: 4
• Feed in steel (up to 800 N): 0.24 mm/rev
• Standard: DIN 335 C

Features & materials

• HSS material
• RUnaTEC coating
• Shank with three flats
• Right‑hand cutting
• Optimised for stationary and manual use
• Reduced feed force, smoother cutting
• Quiet run, optimal countersink finish
• Up to 3× more countersinks possible
• Up to 50% faster countersinking

FAQ

What materials is this countersink intended for?
The countersink is designed primarily for steel; the geometry and RUNaTEC coating make it especially effective for common steel machining tasks.

How does the RUnaTEC coating affect tool life?
The RUNaTEC coating improves wear resistance and reduces built‑up edge, which typically increases service life compared with uncoated HSS tools.

What clamping method ensures secure holding?
Use a standard chuck or collet that engages the shank with three flats to prevent rotation and ensure secure clamping during both manual and machine operations.

Is the 90° angle suitable for standard fasteners?
Yes, the 90° chamfer is a commonly used angle that provides reliable seating for many countersunk fasteners and simplifies inspection procedures.

Can this tool be used in handheld countersinking?
The tool is optimised for both stationary machine use and manual countersinking, offering reduced feed force and a quiet run for safer handheld operations.

Manufacturer/Responsible: Ruko GmbH Präzisionswerkzeuge, Robert‑Bosch‑Strasse 7, 71088 Holzgerlingen